Influence of CuSn thickness on the work function and optoelectrical properties of ZnO/CuSn/ZnO multilayer films

Transparent and conductive ZnO/CuSn/ZnO (ZCSZ) multilayer films were deposited on glass substrates by magnetron sputtering without intentional substrate heating. The thicknesses of CuSn layer was varied from 5 to 20 nm.In the XRD patterns, ZCSZ films with a 5 nm thick CuSn layer had a ZnO (0 0 2) peak, while the 20 nm thick CuSn intermediate films had ZnO (0 0 2) and CuSn (6 6 0) peaks. As the CuSn thickness increased, the sheet resistance decreased from 44 to 16 Ω/□ and the optical transmittance deteriorated due to increased optical absorption.The ZCSZ films with the 5 nm thick CuSn interlayer had the best figure of merit of 4.5 × 10−3 Ω−1. The work function of the films with a 5 nm thick CuSn interlayer was 4.55 eV. These results indicate that the film with a 5 nm thick CuSn interlayer is an alternative candidate for use as a transparent electrode in OLEDs and various displays.